The present invention relates to a door unit for a cold storage whose storage compartment is cooled to extremely low temperatures, for example, −80° C. or lower.
Cold storages of this kind, particularly ultra-deep freezers whose storage compartments are cooled to extremely low temperatures, such as −80° C. or lower have in the past been provided with an inner door for closing an opening of the front surface of the storage compartment in a freely opening and closing manner and an outer door provided outwardly of the inner door for closing an opening of the front surface of a main body in a freely opening and closing manner (refer to, for example, official gazette of Japanese Patent Application Laid Open No. 183,052/2001). Moreover, the outer door of the cold storage of this kind has been formed at its front face or side face with a handle portion with a recess on which fingers put for opening and closing the outer door, and has been provided on the side face with a pivotable latch (engaging member) adapted to engage a latch receiver extending from the side face of the main body for preventing the outer door from being opened.
In this way, in the cold storage of the prior art, when the outer door is to be opened, required are operations first for disengaging the latch and then for putting a hand on the handle portion and pulling it. Moreover, when the outer door is to be closed, after the outer door has been closed, the latch has to be pivotally moved so as to engage a pin on the side of the main body. For these reasons, the opening and closing operations for the outer door are very troublesome. On the one hand, a construction capable of opening an inner door in conjunction with a pivotal movement of a latch of the inner door has been devised in the Japanese Patent Application (patent document No. 1) described above.
The present invention is intended to provide a door unit for a cold storage, enabling easy operations for opening and closing a door by engaging a latch with a latch receiver on the side of a main body in order to eliminate such disadvantages of the prior art.